Antibacterial and antioxidant activity of biosynthesized silver nanoparticles from the high-altitude medicinal plants Rhododendron anthopogen, Neopicrorhiza scrophulariiflora and Rheum australe of Nepal

Abstract

Silver nanoparticles have been massively applied in the medical field including microbial population controls. Green synthesis of AgNPs is more intriguing domain due to possessing environmentally and economically friendly properties. For this experiment, we prepared AgNPs taking the methanolic extract of high altitude medicinal plants namely Rhododendron anthopogen, Neopicrorhiza scrophulariiflora and Rheum australe and antibacterial and antioxidant activity were observed. The biosynthesized AgNPs was confirmed using techniques UV-Vis spectroscopy, FTIR and XRD. Thus, prepared AgNPs demonstrated surface plasmon peak at wavelength nearly 430 nm in UV-Vis spectroscopy. FTIR spectroscopy date explained the role of functional groups in forming stable AgNPs and XRD pattern revealed that the silver nanoparticles were face-centered, cubic and crystalline in nature. The green synthesis of AgNPs working as an antibacterial agent was assessed by zone of inhibition against four readily available bacterial strain Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa and DPPH method is used to calculate antioxidant activity. Taken all together, the highest antioxidant activity IC₅₀ 69.84±0.03 μg/mL was exhibited by the silver nanoparticles of R. australe and the highest inhibition zone measuring16 mm was calculated by N. scrophulariiflora against S. aureus.

BIBECHANA 19 (2022) 133-141